In cellular communication networks, radio base stations (RBS) provide radio network coverage over a coverage area or cell. Communication links between the RBSs of a network and the communication network core segment are referred to as the Mobile Backhaul (MBH) or backhaul. In traditional architectures, both radio and baseband processing are performed in the RBS, which outputs an Ethernet signal which is then transported over the MBH using microwave and/or optical fibre. In some implementations, RBSs may be separated into one or more radio units and one or more baseband processing units, enabling, among other advantages, the optimising of radio unit placement. The radio units may be referred to as Remote Radio Units (RRUs) or as Radio Equipments (REs). The baseband processing units may be referred to as Digital Units (DUs) or as Radio Equipment Controllers (RECs). The communication links between REs and RECs in such deployments are collectively referred to as the Mobile Fronthaul (MFH) or fronthaul, and the interface between REs and RECs is referred to in the following specification as the Fronthaul Interface (FHI). The Common Public Radio Interface (CPRI) specifies an interface protocol for the FHI, managing RBS communication between REs and RECs.
The Xhaul paradigm proposes the combination of MFH and MBH in a common connectivity segment, with the aim of implementing the technological shift that will be required of 5G communication networks. Xhaul proposes the concurrent transport of CPRI traffic from REs towards a centralised REC pool and Ethernet traffic from conventional RBSs towards further aggregations stages.
5G networks will be required to accommodate exponential increases in bandwidth usage compared to current levels. Owing to the bandwidth intensive nature of CPRI, this increase in bandwidth is likely to render the use of CPRI impractical for fronthaul communications: CPRI bandwidth can be up to 30 times higher than equivalent radio signal bandwidth, meaning for a 10 Gbps radio signal, CPRI could attain 300 Gbps, which cannot be managed.